Introduction

Here you’ll find answers to some of the questions that parents often have about this condition. Additional resources are listed
at the bottom of the page. Diagnosis and management information can be found in the Biotinidase Deficiency module, which is written for primary care clinicians but also may be of help to parents and family members.
Information can also be found in the Biotinidase Deficiency Newborn Screening Page. See Biotinidase Deficiency.

What is biotinidase deficiency and what causes it?

Biotinidase deficiency is a genetic disorder caused by the lack of an enzyme that processes biotin, an important cofactor
in the processing of fats, carbohydrates, and protein. Newborns are especially sensitive to biotinidase deficiency, and can
have irreversible vision and hearing loss and seizures, although symptoms of biotinidase deficiency may also first occur in
older children.

What are the symptoms of biotinidase deficiency?

Symptoms may develop as early as the first week of life through childhood. Initial symptoms may include seizures, hypotonia,
hyperventilation, laryngeal stridor or apnea, eczema, hair loss, inflammation of the eyes, yeast infections, and ataxia.

How is it diagnosed?

Most children with biotinidase deficiency are diagnosed by newborn screening tests. Quantitative biotinidase levels can also
be tested if there are concerns in older children.

What is the prognosis?

With treatment, prognosis is excellent. In children who aren't treated, prognosis will depend on the severity of the enzyme
deficiency, with children with less than 10% of normal biotin levels having the worst prognosis.

What is the risk for other family members or future babies?

Biotinidase deficiency is an autosomal recessive condition. Most likely, a child born with biotinidase will have no other
known family members with the condition. Future babies with the same mother and father have a 1 in 4 chance of also inheriting
the gene mutation responsible for biotinidase deficiency.

What treatments/therapies/medications are recommended or available?

Treatment is biotin supplementation depending on the level of existing biotinidase activity.

How will my child and our family be impacted?

With treatment, impact is minimum.

What is the difference between biotin and biotinidase?

Biotin is a vitamin, whereas biotinidase is an enzyme that allows our body to extract biotin from foods. Biotin is important
for reactions necessary to store glucose and fatty acids and to break down branch-chain amino acids. Both the amount of biotin
and the activity of biotinidase can be measured in the blood.

I don't like my child taking medicines, why can't I just serve food that is high in biotin?

All of the biotin available in foods is bound and not available to individuals who can not cleave it from its bound form due
to the deficiency of biotinidase. Although some vegetables may contain some free biotin, it is not enough to provide adequate
supplementation. The biotin in vitamin preparations is not bound (free). [Wolf: 2010]

Biotinidase Deficiency (GeneReviews)An expert-authored, peer-reviewed, current disease description that applies genetic testing to diagnosis and management information
for the condition; National Center for Biotechnology Information, U.S. National Library of Medicine.

Baby's First Test (Genetic Alliance)A clearinghouse for newborn screening information. Provides resources about screening at the local, state, and national levels
and ways for people to share their viewpoints and questions about newborn screening.